Cabbage Trees (Cussoniaspp.)

CabbageTreesThe genus Cussonia contains about 20 species of trees from southern Africa and the island-nation of Madagascar. The best known and most commonly cultivated species is the common cabbage tree (Cussonia spicata), which hails from scattered locations south of the Saharan Desert. It most often grows in open habitats, such as grasslands or just outside forest margins. Although they don’t grow very quickly in their native lands, they are very fast growers when provided with supplemental water.

Basic Description

Most cabbage trees grow about 30 to 40 feet tall, but occasional specimens may become quite large and approach 60 feet in height. They tend to produce a long, thick trunk and a rounded, spreading canopy. Cabbage tree leaves grow in terminal clusters at the ends of short, soft stems. The limbs and stems often grow in a gnarled, twisted fashion. Cabbage trees have bizarre, divided leaves, that are partially responsible for the tree’s unique aesthetics.

Cabbage trees have thick, corky gray bark which would draw more attention, were it not for the plants unusual, spiky inflorescences. Some even describe them as looking like a candelabra.

Medicinal Usage

Many folk remedies rely on cabbage trees, and Western medical professionals are beginning to investigate the properties of various cabbage tree extracts. Local people use a tea made from the bark of cabbage trees to treat malaria and heartburn, while elixirs produced from the roots of the tree are used to treat venereal disease and as a diuretic. While the common cabbage tree is thought to be the primary species used medicinally, but the mountain cabbage tree is also an important medicinal species in its range.

Food Value

While cabbage trees do not represent a significant source of calories for people sharing their native range (nor are they cultivated specifically as a food source), their roots are edible when mashed and boiled. Cabbage trees also provide sustenance for a variety of wildlife species. A variety of caterpillars feed on the leaves of the plant and spin their cocoons on its leaves, while elephants feed on the foliage and seeds.

Select Species

  • Common cabbage trees (Cussonia spicata) – Common cabbage trees are the most commonly seen and cultivated members of the genus. Common cabbage trees thrive in U.S.D.A. Hardiness Zones 9b to 11. Most cabbage trees are tolerant of mild frosts, although prolonged winter cold snaps may kill them off. Mountain cabbage is thought to be more cold tolerant than the common cabbage tree.
  • Mountain cabbage tree (Cussonia paniculata) – Mountain cabbage trees are another relatively well-known species in the genus Cussonia. The mountain cabbage tree often grows in difficult environments, and it typically grows rather slowly. Even the tallest specimens rarely exceed 20 feet in height. The mountain cabbage tree is a popular ornamental in some areas, and, thanks to its modest size, it is often suitable for container plantings.
  • Cape Coast Cabbage Tree (Cussonia thyrsiflora) – Hailing from the South African Cape region, the Cape coast cabbage tree is a hardy species, that can thrive in sandy, acidic or clay-heavy soils. Growing to about 15 feet in height, this evergreen species makes an interesting addition to gardens in Mediterranean climates.

Aralia

aralia_elata_en_fleur4081-1Aralia is a genus of nearly 70 different species that exhibit a diverse array of growth habits. Some reach tree-like proportions, while others are nothing more than shrubs. Some of the large varieties grow as multi-stemmed plants, slightly reminiscent of both bamboo and tropical palms. Many members of the genus bear impressive spines, which lead to common names like spikenard, Hercules’ club and Devil’s walking stick.

Distinctive Leaf Arrangement

Despite their varied characteristics, all species in the genus Araliahave very distinctive, bi-pinnately compound leaves. This means that instead of having leaves that connect directly to the twigs via a small stem (simple leaves), or having leaflets which combine to form a single leaf (compound), Aralia plants have stems that emerge from the twig, and split into a collection of sub-stems, each of which bear several leaflets. At a glance, the leaf appears to contain two ranks of twigs.

Growth and Culture

Aralia species grow naturally in several parts of the United States, so they can often be seen in forests and other natural habitats. However, they are also grown ornamentally as specimens, hedges or borders. In fact, some people have begun growing Aralia species indoors. This is possible in part because many Aralia are understory species that grow well in low light levels, and remain small enough to work in interior applications.

Notable Species

Despite the number common traits found across all species in the genus, Aralia species still exhibit considerable diversity. Some of the most noteworthy species include:

  • Devil’s walking stick (Aralia spinosa) – The Devil’s walking stick is native to the southeastern United States, from upstate New York across to eastern Texas. It prefers well-drained soils and does best in U.S.D.A. Hardiness Zones 4 through 9. Devil’s walking stick is an understory species, that thrives best in partial- to full-sun. Some people eat the tender young leaves of this plant, and Native Americans often incorporated the seeds into their diet.
  • American spikenard (Aralia racemose) –Native to the eastern United States, the American spikenard is an ornamental species, prized for its attractive foliage and dark red fruit. Like many other Aralia species, the American spikenard thrives in shady habitats.
  • California spikenard (Aralia californica) –Unlike some of its eastern relatives, which range through a dozen or more states, the California spikenard is only native to California and parts of Oregon. Although it never becomes woody, this attractive shrub may approach 10 feet in height. Known locally as elk clover, California spikenard features long, divided leaves. A popular ornamental plant, the California spikenard thrives in U.S.D.A. Hardiness Zones 3 through 8.
  • Japanese spikenard (Aralia cordata) – Because it grows as an herbaceous perennial, and its new shoots are eaten by many of those who live alongside it, the Japanese spikenard is also known as mountain asparagus.Reaching about 6 feet in height, Japanese spikenard is a fast-growing plant that thrives best in acidic soils. It commonly grows on wooded hillsides in Eastern Asia.
  • Japanese angelica tree (Aralia elata) –Like those of the Japanese spikenard, the young shoots of the Japanese angelica tree are also widely consumed by humans. This species grows in a tree-like form, occasionally reaching 30 feet or more in height. Like the Devil’s walking stick, the Japanese angelica tree produces sharp bark prickles which help to protect the trees from predators.

Yellow Oleander (Thevetia peruvianasyn. Cascabela thevetia)

Yellow OleanderHailing from Mexico and Central America, the yellow oleander (Thevetia peruviana) is a large shrub or small tree adorned with beautiful yellow to peach flowers, that are very popular among gardeners and homeowners.

Classification

The classification and composition of the genus Thevetia is cloaked in controversy. Some authorities consider the genus to be a part of the genus Cascabela, while others maintain that, while the two groups are closely related, they remain distinct. In either case, there are between three and eight species recognized, with the yellow oleander (Thevetiaperuviana syn. Cascabelathevetia) being the most commonly encountered form.

Toxicity

All parts of the yellow oleander are poisonous – even the milky sap. Ingestion typically leads to cardiac symptoms and electrolyte imbalances, which may be fatal without medical attention. Humans aren’t the only species susceptible to the poisons, as dogs, cats and horses may also suffer ill effects after eating the plant. Nevertheless, a few birds– including Indian gray hornbills (Ocyceros birostris) and several bulbul species (Pycnonotus spp.) — feed upon the plant’s fruit without apparent problem.

The plant’s toxins were so widely respected among Central Americans that the tree was often called the cascabel (a Spanish word often applied to rattlesnakes), which is a reference to its ability to kill as readily as a rattlesnake can.

Growth and Culture

Yellow oleanders are heat-loving trees who prefer warm temperatures and ample sunlight. Plant them in exposed, sunny locations whenever possible, but they will usually survive in areas of partial shade.They are best suited for U.S.D.A. Hardiness Zones 9 and 10, although they are also grown in Zone 8, although precautions must be taken to protect the plants from unusually cold temperatures.

Despite their tropical native range, yellow oleanders grow well in Mediterranean climates – such as those found along much of California’s coastline. While their growing location must be well-drained, they typically adapt well to most soils. While they are generally considered a reasonably drought-tolerant species, your plants will appreciate supplemental water during dry spells.

In general, yellow oleanders are low-maintenance plants, that cause their caretakers little trouble. They are often pruned while small to encourage them to develop a tree-like growth habit, but thereafter, the pruning needs of these small trees are relatively minor. The tallest specimens may reach 20 feet, but most will remain under 10 feet tall. They do produce hard, black to red seed capsules, which present an annual litter problem, but they are otherwise unimposing.

Invasive Species

Thanks to its popularity, yellow oleander is cultivated and grown in suitable climates around the world, including India, Sri Lanka and other portions of South Asia. In many of these places, the plants have escaped cultivation and spread throughout natural habitats, where it has become an invasive species. Although the plant has some wildlife value, it also outcompetes a number of native species, to the detriment of the habitat and greater ecosystem.

Some of the locations in which yellow oleander has become naturalized include Australia, Tanzania, Uganda and portions of East Africa. It has also established itself on many Pacific Islands and some parts of the U.S. One important side effect of this species’ range expansion is the danger it represents to domestic or agricultural animals who may feed upon the plant’s flowers or seeds.

Oleander

OleanderNamed after their superficial resemblance to olive trees, Oleander (Nerium oleander) is an attractive shrub or small tree that thrives in a Mediterranean climate. Originally hailing from North Africa and West Asia, property owners can now purchase oleanders in any of more than 400 different forms.

Size and Shape

Oleanders most commonly grow as large, bushy shrubs, but some specimens develop a tree-like size and shape. Most oleanders are only a few feet tall, but the largest examples may reach 20 feet in height. When large, oleanders tend to exhibit an umbrella-like growth habit. Their stems grow in a relatively narrow clump, but the tops of the branches spread out and cascade toward the ground.

Flowers and Foliage

Oleander leaves are dark green and arranged in pairs (although they occasionally feature a whorled leaf arrangement). An evergreen plant, oleander remains quite attractive throughout the year.

Nevertheless, people do not typically fall in love with oleanders because of their dark green leaves – the flowers are the oleanders’ claim to fame. Sweet-scented and abundant, oleander flowers are as beautiful as they are plentiful; they often bloom throughout the entirety of the warm season. Most oleanders have white or pink flowers, but some cultivars yield flowers ranging from yellow to red.

Unlike many other flowers that depend on the help of insects for pollination, oleanders do not appear to provide any benefit to the insects that visit them. Instead, they appear to use deceptive practices to trick bees into visiting the flowers, even though they produce no nectar on which the bees can feed.

The downy seeds are released from long, thin pods; they take to the air and drift far away when strong winds blow.

Terrible Toxins

While they do not appear to be toxic to many rodents or birds, oleanders are toxic to humans and some other animals. The toxins produced by the plant may cause gastrointestinal upset, heart rhythm problems and even nervous system disturbances – in some cases consumption has resulted in death. However, many tales of oleander poisoning are little more than myths. While you should certainly avoid consuming any part of the plant (all tissues potentially bear the toxic components), human deaths from consuming the plant are relatively rare.

Some people report that contact with the sap of oleanders can cause a skin rash, so caution is advised when contacting the plants. Many insects that feed upon the leaves sequester the ingested toxins and use them as a defense mechanism. Because they are toxic, oleander trees and shrubs typically receive little damage from deer and rabbits.

Geography for Growing

Oleanders grow best in USDA Hardiness zones 8 through 10, but many people have successfully grown them outside of this range. Tough plants, oleanders can handle a wide array of challenges, including high temperatures, periodic drought, periodic flooding, compacted soils, salt spray and high pH levels. However, they are very sensitive to temperatures below about 20 degrees Fahrenheit. When exposed to such chilly temperatures, they almost always suffer damage.

However, if protected from low temperatures, oleanders can thrive just about anywhere. Many people grow them as indoor, potted plants and move them outside during the summer. Alternatively, they can be grown inside the climate-controlled confines of a greenhouse.

Custard Apples

Custard Apples

Custard Apples

The term custard apple tree is applied in two different ways: Some use it to describe all members of the genus Annona, while others only apply the name to the species Annona reticulata. Fortunately, while the genus Annona is quite large (with approximately 150 to 175 species, depending on the authority consulted), the species all share a variety of similar traits.

Most custard apple tree species are native to Central America and Africa, although several species have been domesticated and are grown in suitable climates the world over. The fruit of several species has significant commercial value, particularly in the developing world.

Size and Shape

Custard apples are medium-sized trees that usually reach heights of between 15 and 40 feet. They aren’t considered especially attractive trees, so they are typically grown for food production rather than as ornamentals. Additionally, custard apple trees have very soft wood that breaks easily – particularly when the branches are weighed down with a full fruit crop. Most commercial custard apple farms utilize wind breaks to help protect their trees and maximize their crop.

Nevertheless, custard apple trees can be planted ornamentally, although they only thrive in U.S. Hardiness Zones 7 through 9. Skillful pruning can improve their appearance and help keep them looking their best. Despite the fact that they aren’t ideal shade trees, they do offer most of the same benefits that similarly sized trees do (such as providing shade and wildlife habitat as well as reducing local temperatures).

Their deciduous leaves are about 5 to 8 inches long and rather narrow. They are typically dark green on their top surface and lighter green beneath.

Fruits and Flowers

The flowers of custard apple trees are somewhat bizarre-looking. In fact, they never open completely the way most other flowers do. They bear three extraordinarily long outer petals and three smaller inner petals (the inner petals are very difficult to see). This flower construction belies their close relationship with paw paws (Asimina spp.). Large horned beetles appear to be the primary pollinators of most Annona species.

The resulting fruit is somewhat large and equally strange. Varying in shape from oblong to spherical (and occasionally heart-shaped), the ripe fruit varies between yellow and red in color. The taste is described as being custard-like, which is the reason for their common name.

Growing Tips

Custard apples grow best in very well drained soils. Although they do produce a significant taproot extending vertically below the trunk, the bulk of the absorbing roots reside in the upper layers of the soil. However, these trees are very susceptible to root rots and bacterial wilt. In fact, The Queensland Department of Agriculture and Fisheries recommends that growers refrain from planting custard apple trees in soils that formerly harbored tomatoes, potatoes, eggplant and several other common crops, due to the likelihood that bacterial spores may already lurk in the soil. However, root-zone issues aside, custard apples do not often succumb to many pests and diseases that afflict other fruiting trees.

Custard apple trees require warm temperatures to thrive, and they grow best in areas with long, humid summers and mild, dry winters. Established custard apple trees can survive moderate droughts, but without ample rainfall and relative humidity levels of 70 percent or more, custard apple trees may shed their leaves and produce a minimal crop.

Toxic Properties

Several components within custard apple trees are potentially bioactive, and several primitive cultures use different parts of the plants for medicinal purposes. Some of the plants in this genus produce toxic seeds, which can cause a degenerative neurological condition in humans. Strangely, this only seems to occur on the island of Guadeloupe.

The leaves of custard apple trees also bear several bioactive compounds. They not only possess insecticidal chemicals; their tannins are used to make dyes.

 

Pawpaw Tree

A couple of different species in the genus Asimina go by the name pawpaw, but the common pawpaw (Asimina triloba) is far and away the most commonly encountered species.

Whereas the common pawpaw is found throughout much of the eastern United States, all other members of the genus are restricted to Florida, Alabama and Georgia. Authorities differ on the number of species in the group, with some only recognizing two and others recognizing as many as 10.

While pawpaw trees are somewA Favorite Fruithat interesting looking (especially when contrasted with most other native trees), they offer little value in an ornamental context. Their primary claim to fame is their highly unusual fruit.

A Favorite Fruit

Pawpaw fruit defy easy description. Reaching up to 6 inches in length, they are the largest edible fruit that native to the United States.  Although they start out green, they often bear browns, yellows or even purple tones upon ripening. Technically a type of berry, pawpaw fruits contain a number of hard, inedible seeds.

Most people describe their taste as being similar to that of a banana (they are, in fact, used frequently in place of bananas in desert recipes), while others liken their flavor to that of a mango. Some note hints of papaya or strawberry. Their texture is better characterized as extremely soft and custard-like.   

Those who enjoy the taste often prize them greatly, as they are not easy to acquire via commercial means. Pawpaw fruits are not easy to store for extended periods of time and shipping them is equally problematic – they turn to mush in short order. Some small-scale farmers have begun growing them for local markets, but short of the development of a storable cultivar, they are unlikely to become commonplace in your local grocery store.

However, pawpaws are sometimes available in frozen or preserved form. Some manufacturers have even started creating pawpaw ice cream.

A Taste of the Tropics

Pawpaws look somewhat out of place in eastern forests. Instead of the small, thin, finely toothed leaves of maples (Acer spp.), elms (Ulmus spp.) and birches (Betula spp.), these bottomland-inhabiting trees have large, smooth-edged leaves that look like they belong in a tropical rainforest. Although they can grow to proper “tree-sized” proportions, most wild specimens are rarely more than scraggly denizens of the understory.

While their physical characteristics are partially a manifestation of their habitat adaptations (for example, their large leaves are an adaptation that enables them to collect as much light as possible in the dim forest understory), they are also a manifestation of their evolutionary relationships. Pawpaws are members of the family Annonaceae, which primarily contains trees with tropical distributions. Some of its closest relatives living in the same forests include the magnolias (Magnolia spp.) and tuliptrees (Liriodendron tulipifera).

Funny-Looking Flowers

Pawpaw flowers are very interesting-looking. They bear six petals arranged in two rows – one outside row and an offset inside row. Somewhere between maroon and brown in color, the medium-sized flowers may occur singly or in groups. They’d be relatively inconspicuous were it not for their size.

They are also relatively scent-free, which is good; what smell they do emit is not terribly pleasant. In fact, the primary insects that pollinate the flowers (several beetle species) are those attracted to the smell of decay. Because these are not very effective pollinators, pawpaws produce relatively few fruit relative to the number of flowers they bear.  

Subpar Seed Dispersal

Fruit-set is not the only thing with which pawpaw trees struggle: They are also poor seed dispersers. While plenty of animals also find pawpaw fruits to be delicious — raccoons, coyotes, foxes and opossums eagerly consume the fruit – few of them ingest, and ultimately disperse, the seeds.

To help cope with this evolutionary challenge, pawpaws often reproduce by forming large spreading colonies in hospitable locations. Some scientists have suggested that the poor dispersal pattern of pawpaws is the result of the extinction of a former predator (most likely a big herbivore that could ingest the fruit whole). Once these creatures died off, humans became the primary means by which pawpaw seeds have traveled ever since.

 

Yucca

Yuccas

Yuccas (Yucca) are iconic perennials, found across a wide geographic area, stretching from Canada to South America. The fifty-odd species that comprise the genus inhabit a variety of different climate zones across this range, but most are native to arid habitats.

Because they provide the raw materials necessary for making many basic necessities, yuccas have been important to people for hundreds of years; while they are not commercially important in the modern world, several species are very popular, drought-tolerant ornamentals.

Basic Biology

Most yuccas possess a few key traits that characterize the entire genus. These include the presence of long, pointed leaves that arise from a dense rosette, and tall, “floating” inflorescences. Some forms remain close to the ground and superficially resemble a tuft of giant grass, while others (especially some of the most famous members of the group) produce a tree-like growth form.

Arid Adaptation

Taken as a whole, the genus Yucca displays a diverse array of adaptations that help them survive in arid habitats. Many of these traits make these plants particularly well suited for ornamental use in Southern California. Yucca plants thrive best in full sun exposure, but they can thrive in most well drained soils, and require very little (if any) supplemental irrigation once established.

Most of the species possess thick leaves and many feature a thick wax layer on the surface of the leaves; both adaptations help slow the rate of transpiration, and therefore, reduce the amount of water the plants lose. Some species shed their leaves and become dormant during dry, hot summers. In doing so, the plants typically shed their leaves to halt transpiration altogether. Additionally, the shed leaves provide some protection against the sun’s harsh rays.

Yucca Pollination

While a few yuccas are capable of self-pollination, most require crosspollination to produce seeds. Accordingly, most yucca species relies on insects – specifically, a group of lepidopterans called yucca moths – for pollination.

While feeding on the nectar produced by yucca flowers, the moths ferry pollen from male flowers to females, thus ensuring crosspollination. Because yucca moths also deposit their eggs on the female flowers, the hatching larvae enjoy a ready food source: the developing seeds.

Notable Species

Several yucca species are particularly interesting. Some of the most notable species include:

Joshua trees (Yucca brevifolia) are often mistaken for true trees, as they produce tall, thick trunks that branch in multiple locations. Found throughout the Mojave Desert, Joshua trees actually serve as an indicator species for the Mojave community. Joshua trees were important to the Cahuilla people (historic inhabitants of the Mojave region), who used the tough leaves of the plants to make sandals and other durable goods, and collected the flower buds and seeds as a food source.

Like Joshua trees, soaptree yuccas (Yucca elata) are native to the American southwest, but they inhabit the Sonoran and Chihuahua Deserts, rather than the Mojave. Also like Joshua trees, soaptrees provided a variety of resources for Native Americans living alongside them. In addition to stiff plant fibers used to produce baskets, sandals, cordage and similar items, a soapy substance found within the plant’s trunk and roots was harvested for use as a soap or shampoo.

Spineless yuccas (Yucca elephantipes) are quite tree-like, and they often produce several different “trunks.” Perhaps unsurprisingly, the spineless yucca is the tallest member of the genus Yucca, and it occasionally reaches 30 feet in height.

Spineless yuccas are popular ornamentals in many warm regions, including not only California and Arizona, but also the relatively humid south Florida region. Unlike many other yuccas, including the aptly named needle-palm (Yucca filamentosa) and Spanish dagger (Yucca gloriosa), which possess stiff terminal spines that probably serve to discourage predators; spineless yuccas lack hazardous terminal spines.

Thanks to their striking pale blue leaves, beaked yuccas (Yucca rostrata) are popular ornamentals. These yuccas also grow like small trees, and often reach heights of 15 feet or more.

Cashew tree

Cashew Trees

Most famous for the delicious nuts they produce, cashew trees (Anacardium occidentale) are medium-sized evergreen trees, historically native to Brazil.

Aside from their well-known and commercially important tree nuts, cashew trees also produce an edible accessory fruit, commonly known as a cashew apple.

In a culinary sense, cashews work in the same contexts as most true nuts do, so they are often referred to as such. However, in the botanical sense, cashews are seeds, not nuts.

Traits of the Tree

Cashew trees are medium-sized, evergreen trees that reach heights of about 20 to 40 feet. Their foliage is quite dense and attractive, and typically forms a spreading crown.

The leaves are smooth, leathery and rounded at the distal end, with prominent veins. Cashew trees produce a well-developed network of roots, which help them to survive during times of minimal rainfall. When grown in areas with deep, loamy soil, cashew trees produce a large taproot, which helps them access deep-water reserves. This dense network of roots makes transplantation somewhat problematic.

Cashew trees produce relatively small, pink- to magenta-colored flowers, which emerge from the current season’s growth. The flowers may be male, bisexual or female, although female flowers are relatively rare on the trees.

Poisonous Relatives

Although it seems surprising, cashews are not-too-distant cousins of poison ivy (Toxicodendron radicans) and poison oak (Toxicodendron diversilobum). Accordingly, some parts of cashew trees contain urushiol – the problematic compound found in the sap of these and other, related plants.

One part of the tree that holds a significant quantity of the toxic compound is the seed’s outer shell. This makes shelling the nuts difficult, and most commercial operations rely on special equipment to shell and clean the nuts. In fact, the University of Florida discourages private individuals from trying to harvest home-grown cashew nuts, as the caustic fluid can cause severe blistering if it contacts the skin.

Geographic Range and Preferred Climate

Cashew trees require relatively warm temperatures and they are very susceptible to frost damage. They are primarily grown between 25 degrees North and 25 degrees South latitude. The trees require a minimum of about 40 inches of annual rain, although 60 to 80 inches of annual rain is ideal.

Although native to northeastern Brazil, cashew nuts are now grown in several countries around the world. Vietnam produces more cashews than any other country, but India, Nigeria, Cote d’Ivoire and Benin also produce significant amounts of the nuts.

Growing Your Own

In spite of the problems associated with harvesting the seeds, many people like growing cashew trees as attractive ornamentals (although you can harvest the cashew apples produced by the trees, which, due to their short shelf life are typically not available in American markets). Cashew trees are most commonly grown in this fashion in south Florida, but they may thrive in southern California if nurtured.

The commercial harvest of cashews requires a long-term commitment, as it typically requires eight years for the plants to produce an economically significant harvest. However, dwarf varieties have been developed recently, which become economically viable at the end of their third year. Additionally, these dwarf varieties produce more than three times as many seeds per acre as wild-type cashew trees do.

Starr Ficus macrophylla

Santa Monica’s Special Trees

Santa Monica stands in the top tier of tree-friendly cities in both the country and the world – no small feat for a city that is built on a historically tree-poor habitat.

This is only possible when local communities embrace their urban forest and appreciate the benefits provided by these leafy neighbors.

Typically, this necessitates things like allocating sufficient funding for tree care, adopting protective ordinances, implementing regular maintenance schedules and planning for removals and replacements. But while these types of day-to-day tasks and strategic initiatives are important, they often fall short of inspiring a love or admiration for trees.

Reduced to a series of costs and benefits, trees become just like any other asset or liability on the ledger. However, cities like Santa Monica understand that some individual trees become so interwoven into the local culture and ecosystem that they deserve special recognition and protection. These “Landmark Trees” are a special source of pride for Santa Monica’s residents, who currently apply this moniker to three trees within the city limits.

Moreton Bay Fig

The incredible Moreton Bay fig (Ficus macrocarpa) growing on the grounds of the Fairmont Hotel was first designated as a landmark tree in 1976. One of the largest specimens in the country, the incredibly picturesque tree was planted in the early 1880s. Interestingly, the tree appears to have been offered to a local bar of the time by an Australian sailor, who had no other way to cover his bar tab.

Like most other Moreton Bay figs, this tree has a heavily buttressed root system that gives the tree an enchanted look.

Deodar Cedar

Also known as Himalayan cedars, deodar cedars (Cedrus deodara) are relatively massive conifers, native to south Asia. This landmark specimen, which was planted in its 5th street location around the beginning of the 20th Century, has never been pruned — branches still cling to the lower portions of the trunk. Standing about 60 feet high with a trunk over 4 ½ feet in diameter, the iconic evergreen is an impressive sight. The deodar cedar first gained landmark status in November of 2002.

Yate Tree

The Hill Street yate tree (Eucalyptus cornuta) – often simply referred to as a eucalyptus tree – received landmark status in 2006. This particular tree is especially interesting, as it appears to have grown naturally – that is, without being deliberately planted by humans. Instead, the seeds were either dispersed by the wind or cached and forgotten by local wildlife.

The tree rises about 60 feet into the air and bears two trunks – a condition arborists refer to as co-dominant leaders. The smaller trunk is about 45 inches in diameter, while the larger trunk measures about 49 inches in diameter.

Former Landmark Tree: The 24th Street Blue Gum

While landmark trees are afforded greater protection than most trees, this protection is not permanent. Some landmark trees become hazardous with age, thereby necessitating their removal. Such was the case with the immense blue gum (Eucalyptus deanei) on 24th street, which was removed in September of 2012, in response the failure of several large limbs. Until it was removed, the tree soared 130 feet into the sky and boasted a trunk diameter of 17 feet, making it the largest blue gum tree in the country. The tree had appeared in numerous books, including “The Trees of Santa Monica.”

Incense Cedars (Calocedrus decurrens)

Named for the spicy aroma of the wood, incense cedars are interesting trees. Close relatives of the northern white cedars (Thuja spp.); incense cedars are relatively rare in the natural world, although they were formerly common. Considered at one time to be represented a single species, botanists now recognize several different species of incense cedars. The only North American native, California incense cedars (Calocedrus decurrens) range from California to northern Oregon, while C. formosana, C. macrolepis and C. rupestris grow in Taiwan, China and Vietnam, respectively. Additionally, paleobotanists have described an extinct species – C. huashanensis – that formerly grew in China.

Size and Shape

Incense cedars are long-lived trees that often reach ages in excess of 500 years. Other forest species often outcompete these trees, and retard their growth rate. However, over the course of their long lives, incense cedars often reach moderately large sizes. Typical specimens grow to between 60 and 80 feet, although some giants of the Sierra Nevada Mountains grow twice as tall.

Because they are drought resistant, relatively pest free natives of California, they can make a wonderful addition to your property. Their form and foliage make them aesthetically pleasing, while their extremely dense foliage makes them excellent for windscreens. These trees help support wildlife as the tiny seeds that emerge from the 1-inch-long cones feed a variety of songbirds and native rodents.

Can’t Stand the Heat?

Incense cedars are well adapted for hot, parched conditions; once established, they are remarkably drought tolerant. According to U.S. Forest Service, incense cedars tolerate dry conditions better than sugar pine, Douglas firs and grand firs, although ponderosa pines are better equipped to deal with drought in sandy areas than the cedars. (Oliver) While they often become canopy trees on southern or southwestern hillsides, other species outcompete incense cedars on moist sites, causing them to remain much smaller. Although high-intensity crown fires kill incense cedars, they often survive low-intensity ground fires.

Variation and Variety

Incense cedars vary slightly based on their location. Southern California specimens reach shorter heights than their northern relatives do. Additionally, these southern individuals often have shorter branches, and they tend to exhibit a more columnar growth form. Perhaps unsurprisingly, these southern varieties are more susceptible to frost damage than their northern counterparts are.

Commercial Uses

Incense cedars make wonderful ornamental trees, even well-outside their native range. They are popular in Europe and along the Atlantic seaboard of the United States. Incense cedars require partial to full sun, well-drained soils and protection from strong winds. Because they grow quite large, they are best planted on large properties where they have ample room. Fortunately, for those who share space with deer, the hoofed browsers rarely feed on incense cedars.


Because the wood of incense cedars resists decay — even in the presence of moisture — it is often used in outdoor construction. The wood also accepts paint well, leading many to use it for building picnic tables, exterior siding and fence posts. However, one of the most common uses of incense cedar is in the manufacture of pencils.

 

Threats

Good ‘ol root rot brings more incense cedars to their knees than any other cause, although pocket dry rot (Tyromyces amarus) is also a threat to these gorgeous conifers. This fungus causes significant internal decay, which ultimately compromises the tree’s structural integrity. Healthy bark provides an effective barrier against fungal colonization, but knots and damaged areas are vulnerable. Pocket dry rot primarily affects those trees that grow on favorable sites; for example, some stands in the Sierra Nevadas exhibit 100 percent colonization of the mature specimens.

Incense cedars may also serve as the host for incense-cedar mistletoe (Phoradendron juniperinum libocedri), but the parasitic epiphyte rarely causes tree death. A number of insects feed on these trees, but few cause serious problems. The only common foliage disease – Gymnosporangium libocedri – rarely causes the trees to die.

 

References

Oliver, R. F. (n.d.). Incense-Cedar. U.S. Forest Service.